Elevator control system



June 29, 1937. E. H3 VEDDER ELEVATOR CONTROL SYSTEM Filed NOV. 13, 1934 7a as@ WITNESSES:

vPatented June 29, 1937 Y PATENT OFFICE ELEVATOR CONTROL SYSTEM Edwin H. Vedder, Swissvale, Pa., assigner to Westinghouse Electric '& Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 13, 1934, Serial No. 752,798 1a claims. (ci. isi-29) My invention relates, generally, vto elevator systems, and it has particular relation to elevator systems for controlling the operation of a motor employed to` operate the elevator car in a- .15 devices is illustrated in Patent No. 1,769,054 to W. F. Eames, issued July 1, 1930, and in Patent No. 1,865,937 to H. W. Mattingly, issued July 5, 1932, both of which patents are assigned to the assignee of this application. It has beenv desir'- 20 able, however, to improve upon the control systern and apparatus shown in the patents and on the control systems and apparatus known to those skilled in the art. For that purpose, the control system and apparatus illustrated and 25 described herein have been made.

The object of my invention, generally stated, is to provide an elevator control system which shall be simple and eficient in operation and which may be readily and economically manu- 30 factured and installed.

The principal object of my invention is to provide for employing light-sensitive devices for controlling the operation cf an elevator car.

An importantv object of my. invention is to 35 provide for initiating a vslowf-down' sequence for a motor operated elevator car to bring the car to rest at a desired floor level.

A further object of my invention is to provide for increasing the sensitivity and accuracy of l 40 light-sensitive devices used for controlling the operation ofa motor operated elevator car.

Still anotherl object of my invention is to provide for preventing the functioning of a light-- quencies above a predetermined'frequency and currents having steep wave fronts to a spacedischarge devicevused 1n conjunction with manT sensitive equipment for controlling the func# 55 tioning of a motor-operated elevator car.-

A Other objects of my invention will in part be obvious and in part appear hereinafter.

Accordingly, my invention is disclosed inthe embodiment hereof shown in the accompanying drawing and comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated 'in the appended claims. Y

For a emore complete understanding of the nature and scope of my invention, reference may be 'had to the following detailed description taken in connection with the accompanying drawing, in which the single figure diagrammatically represents a concrete embodiment of my invention.

l According to my invention, an elevator car, which is movable in a hatchway by means of a motor, is provided with a light-sensitive unit. This unit comprises a light source arranged to illuminate a photo-electric cell. The photoelectric cell is connected to control the functioning of a space discharge device or grid glow tube. When the photo-electric cell is illuminated, an energizing potential isapplied to the grid glow tube and the latter remains in the non-conducting state. However, as soon as the rays of light falling on the photo-electric cell are intercepted,

the grid glow tube is rendered conducting.

In order to intercept the rays of light falling on the'photo-electric cell, operating shields are placed in the hatchway. A shield is provided individual to each iioor and is so spaced relative to the light-sensitive unit carried by the car, that the desired functioning thereof may take place in suiiicient time to cause the car to be brought to the level of the floor.

As soon as the grid glow tube is rendered conducting, the operating winding of a slow-down relay is energized. 'I'he operation of this relay initiates a slow-down sequence for stopping the motor, which operates the elevator car at the proper rate, by any suitable well known means.

In order to ensure that the photo-electric cell is 4illuminated before the grid `glow tube is energized with a view to preventing a false operation thereof, the light source is energized as soon as the car approaches the floor where a call is registered and a predetermined time thereafter the grid glow tube is energized. This time Vdelay is desirable in order to permit the light source, which usually is an incandescent lamp. to be brought to its operating brilliancy for thev pun. pose of energizing-the photo-electric cell to preto complete the energizing circuit to the grid glow v vent the grid glow tube from becoming conducting. f

The grid glow tube is connected for energization to the secondary winding of a ltransformer; the circuit including the operating Winding of the slow-down relay and the grid glow tube. vIn view of the fact that the grid glow tube is a highly sensitive device and may be rendered conducting under certain conditions when such operativon is not desired, it has been found highly desirable tube by contact members interposed in the circuit including the secondary Winding of thel transformer rather than in the primary winding: thereof. If the energizing circuit for the grid glow tube is completed in the primary winding of the transformer, it has been found that the transient effects due to various magnetizations of the iron core of the transformer may be sufficient to ionize the gasin the grid glow tube and to cause it to become conducting at a time when such action is not desired.

Since the light sensitive u'nit is mounted on the v car while the remaining 'apparatus is mounted in the penthouse, it is necessary to-provide connections therebetween by means of conductors which are free to swing in the hatchway, as will be readily understood. These conductors function in somewhat the same manner as the antenna of a radio receiving set and in many instances high-frequency currents are induced therein due to switching conditions in the control system of the elevator or adjacent apparatus, These highfrequency currents, in some instances, are suicient to cause ionization in the grid glow tube and as a result it becomes-conducting. In order to avoid the false operation of the unit as a result of the superimposed high' frequency, a filter is provided and connected in circuit with the grid glow tube. A

The lter not only prevents the application of high-frequency currents to the grid glow tube, which would tend to ionize the gas therein, but it also prevents the application to the grid glow tube of the steep Wave iront-of the control current, and, as a result, causes the grid glow -tube to be responsive only to the control of the photoelectric cell.

For the sake of clarity and in order to reduce the circuit connections and complications thereof to a minimum, .I have illustrated my invention in schematic form. No attempt has been made to show the elevator car or associated control equipment other than that which .is directly aifected by the control system which is organized in accordance with my invention. It will be readily appreciated by those skilled in the art that any of the various forms of control systems may be employed for controlling the operation of the motor which is used for operating the elevator car.

Referring now particularly to the single gure of the drawing, the reference character i designates,- generally, a light-sensitive unit which is arranged to be carried on an elevator car. This unit comprises a. light source 2, which may be a standard incandescent lamp, a photo-electric cell 3 Aand a space-discharge device or grid glow tube I. As illustrated, the grid glow tube l is provided with an anode 5, a cathode 6, a grid 1 and a shielding electrode 8. The particular construction of the grid glow tube 4 is set forth, in detail,

ever, that any other suitable type `of discharge device may be provided without departing from the scope of this invention.

It will be observed that the shielding electrode 8 is connected through a resistor .9 to the cathode 6 for a purpose which is fully set forth in the aforesaid patent to Knowles. It will also be noted that the photo-electric cell 3 is connected in series circuit relationwith a capacitor I0 and a resistor Il and between the anode 5 and the cathode 6. It will also be noted that the 'common terminal between the capacitor ID and the photo-electric cell 3 is connected to the grid 1. When the photoelectric cell 3 is illuminated, the resistance thereof is at a minimum and the grid 1 and cathode 6 are at substantially the same potential. When the light rays falling on the photo-electric cell are intercepted this condition no longer exists, and with operating potential applied between the Ianod'e 5 and the cathode 6, the grid glow tube 4 is rendered conducting.

In :order to prevent the application of highfrequency currents and currents having steep wave fronts to the grid glow tube 4, an inductor l2 is provided. A capacitor i3 is connected in shunt circuit relation with the inductor i2 and the grid glow tube 4, in order to by-pass the high frequency currents, which would otherwise pass through the grid glow tube 4 and might cause its ionization and its subsequent breakdown.

In order to intercept the light rays from the source 2, which fall on the photo-electric cell 3, an operating shield I4 is provided in the hatchway. A shield i4 is provided individual to each floor and, when it occupies the position represented by the dotted lines between the light source 2 and the photo-electric cell 3, the rays falling on the latterare intercepted, the grid 'l no longer remains at the same potential as the cathode 6 and the grid glow tube 4 becomes conducting. t

As soon as the grid glow tube 4 becomes conducting, an operating winding Iw of a slowdown relay is energized. Suitable circuits, not shown, are then completed for initiating the slow-down sequence for the elevator motor. This sequence may be controlledv by additional lightsensitive units similar to that illustrated herein or it may be controlled by any other suitable control system. Since the system for effecting the slow-down sequence forms no part of this invention, only the operating winding Iw of the slow-down relay has been illustrated herein.

It will be observed that the operating winding [Sw is energized from the secondary winding I8 of a transformer shown generally at i9, the primary winding 20 of which is connected for ener- `gization between conductors 2i and 22. The

conductors 2| and 22 may be connected to a suitable source of alternating current such as a `connecting the light source 2 to the control conductors 2l and 22.

As soon as a call is registered on a door, contact members 21a. are closed. The circuits and apparatus for closing contact members 21a are well known to those skilled in the art and, therefore, they will 'not be further illustrated or described herein. In response to the closing of contact members 21a, a floor segment 28a is connected tothe energized conductor 2|. In like" manner, if ay call exists on another-door, (contact members 2lb, for instance, will be closed, connecting :door segment 28b' tol the energized conductor 2|.

vAs the car approaches the floor at which the call is registered, brush 2 9 'engages the licor segment 28a and completes an obvious venergizing circuit for the operating winding 30w of a control relay through contact members 3ia of a speed relay 3l, which contact members are closed` as long as the elevator car is in motion.

As soon as the operating winding 30m is energized, contact members Spa are closed to complete a holding circuit around the contact mem- `I at the potential of the cathode 6.'

As has been set forth hereinbefore, it is desirable to prevent the energization of the` grid glow tube 4 until a` predetermined time after the light source 2 has been energized. For this purpose, it is desirable-to prevent the closure of contact members 30o, which are operated on energization of the operating winding 30w until some time after contact members 30h have been closed. Any suitable means may be provided whichwill effect this time delay. I have illustrated diagrammatically a dashpot 32 which is associated with the contact members 30e and is arranged to prevent the closure thereof until a predetermined time after contact. members 30h are closed. vIt Will-,be understood, however, that any other suitable type of time delay apparatus may be employed inj order to prevent the energization of the grid glow tube 4, until after the photo-electric cell 3 has been fully illuminated.

.It will. be observed that the contact members 30o are provided inthe circuit which includes the secondary winding I8 of lthe transformer vi9 rather than in the circuit which includes the r primary winding 20. These connections are provided, as set forth hereinbefore, in order to reduce to a minimum the eiect of transients in the circuit including the grid glow tube 4, which may result `from' the magnetic condition of the core of the transformer i9.

Since certainfurther changes may be made in the above construction andl different embodi-` ments of the invention may be made Without departing from the scope thereof; it is intended that all matter contained in the above descrip- V tion or shown in the accompanying drawing shall light source disposed in operative relation thereto and carried by the car,-a transformer havingl a primary winding connected to a source of alternating current and a secondary winding, a control relay operable in response to a oor call and having contact members, said bontact members being disposed on operation of said relay to eifect the energization of said light source and to connect said secondary winding to energize said llight-sensitive means, a shield mounted in the hatchway for controlling the illumination of said light-sensitive means in accordance with the position of said car with reference to said iioor, and a slow-down relay responsive to a predetermined change of the condition of illumination of said light-sensitive means for eiecting the stopping of lthe motor to bring the car to the iloor level.

2. vIn a control system for a motor-operated elevator car -movable in a hatchway relative to one or more iloors, in combination; a light-controlled unitcarried by the car including a light source and a light-sensitive device disposed in operative relation thereto, and a space-discharge device disposed to be rendered conducting when said light-sensitive device is in a predetermined condition of illumination; a transformer having a primary winding connected to a. source of alternating current and a secondary winding, control means operable in response to a floor call to connect said secondary Winding for energizing said space-discharge device, a shield mounted in the hatchway for controlling the illumination of said light-sensitive means in accordance with the position of said car with reference to said iloor, and a slow-down relay disposed to be operated in response to a predetermined change of the con dition of illumination of said light-sensitive means for effecting the stopping of the motor to bring the car to the iloor level. I

3. In a'control system for a motor-operated elevator car movable in a hatchway relative to, one or more iioors, in combination; a light-controlled unit carried by the car including a light source and a. light-sensitive device disposed in operative relation thereto, and a space-discharge device disposed to be rendered conducting when said `light-sensitive device is in a predetermined condi- .l current and a secondary winding, control means operable in response to a floor call and having a plurality of sets of contact members, one of said sets ofV contact members being disposed to effect the energization of said light source and another of said sets of contact members being disposed to connect said secondary winding to energize said space-discharge device, a shield mounted in the hatchway for controlling the illumination of y said light-sensitive means in accordance with the position of said car with reference to said floor, and a. slow-down relay disposed to be operated in response to a predetermined change of the condition of illumination of said light-sensitive means for effecting thev stopping of the motor to bring the car to the floor level.

4. In a control system for a motor-operated elevator car movable in a hatchway relative to one or more floors, in combination; a light-controlled unitcarried by the car including a lightsource and a light-sensitive device disposed in operative relation thereto, and a space discharge device Vdisposed to be rendered `conducting when said light-sensitive device is not illuminated; a transformer having a primary Winding connected to a source of alternating current Yfand a secondary Winding', control means operable in response to a iioor call and having a plurality of setsfof contact members, one of said sets of contact members being disposed to immediately eiect the energization of said light source and another of said sets of contact members being disposed to connect `said secondary winding to energize said space-discharge device a predetermined time thereaiter, a shield individual to said floor and mounted in the hatchway for -interceptng the rays of light falling on said light-sensitive device from said light source, and a slow-down relay disposed to be energized When said space-discharge device is rendered conducting for eiecting the stopping of the motor to bring the car to the floor level.

5. In a control system for a motor-operated elevator car movable in a hatchway relative to a floor in'which energizing currents due to transient electrical conditions are caused to flow, in combination, light-sensitive means and a light source disposed in operative relation thereto and `carried by the car, 'circuit means for connecting said light-sensitive means to a current source, means for preventing the application to" said light-sensitive means of said energizing currents resulting from said transient electrical conditions, a shield individual to said floor and mounted in the hatchway for intercepting the rays of light falling on said light-sensitive means from said light-source, and a slow-down relay disposedv to`r be operated on the interception of the light rays for effecting the stopping of themotor to bring the car to the floor level.

6. In a control system for a motor-operated elevator car movable in a hatchway relative to a oor, in combination, .light-sensitive means and a light source disposed in operative relation thereto and carried by the car, circuit means for connecting said light-sensitive means to an alternating current source, meansv for .preventing the vapplication to said light-sensitive means of frequencies differing'from that obtained fromsaid alternating current source,`a shield individual to said iioor and mounted in the hatchway for intercepting thearays of light falling on said lightsensitive means from said light source, and a slow-down relay disposed to be operated on the interception of the light rays for effecting the stopping of the motor to bring the car to the floor level.

7. In a control system for a motor-operated elevator car movable in a hatchway relative to one or more floors,`in'combination; a light-controlled unit carried by the car including a light sou-rce and alight-sensitive device disposed in operativev relation thereto, a space discharge device disposed to be rendered conducting when said light-sensitive device is not illuminated, and a filter connected in circuit with'said space-discharge device for preventing the application charge device .for preventing the application thereto of currents having frequencies differing from a predetermined frequency; a control relay operable in response to a iioor call and disposed to effect the energizationV of said light-controlled unit, a shield individual to said floorv and mounted in the hatchway for intercepting the rays of light falling on said light-sensitive device from said light source, and a slow-downrelay disposed to be energized when said space-discharge device is rendered conducting for effecting the vice disposed to be rendered conducting when said light-sensitive device is not illuminated, and

a filter connected in circuit with said space-disp charge device for preventing the application thereto of currents having frequenciesl differing" from a predetermined frequency; a shield individual to said iioor and mounted in the hatchl way for intercepting the rays of light falling on said light-sensitive device from said light source,

-and a slow-down "relay disposed to be energized when said space discharge device is rendered conducting for effecting the stopping of the motor to bring thacar to the floor level. 8. In a control system for a motor-operate elevator car movable in a hatchway relative to one or more floors, in combination; a. light-controlled unit carried by the car including a light source Vand a light-sensitive device disposed in operative relation thereto, a space-discharge device disposed to be rendered conducting when said light-sensitivegdevice is not illuminated, and a nlter connected in circuitwith said space-disthereto of currents having Ifrequencies differing from a predetermined frequency; a control relay operable in response to a floor call and disposed to energize said light-controlled unit, means for preventing the application of energizing potential fto said space-discharge device until the expiration of a predetermined time after said light l source isl energized, a shield individual to said floor and mounted in th hatchway for intercepting the rays of light falling on said lightsensitive device from said light source, and a slow-down relay connected in series circuit relation with said space-discharge device and disposed to be energized when said space-discharge device is rendered conducting for effecting the stopping of themotor to bring the car t9 the floor level.

l0. In a control system for a motor-operated elevator car movable in a hatchway relative to a floor, in combination, light-sensitive means and a light source disposed in operative relation thereto and carried by the car, a iilter also carried by the car and connected in circuit with said light-sensitive means. for preventing the application thereto of currents having frequencies differing from a predetermined frequency, a transformerhaving a pnmary winding connected to a source of alternating current and a secondary winding, a controllrelay operable in response to a iioor call and disposed to effect the energization of -aid light source and to connect said secondary winding to energize said light-sensitive means, a shield individual to said oor -and,

mounted in the hatchway for intercepting the rays of light falling on said light-sensitive means from said light source, and a slow-down relay disposed to be operated on the interception of the light rays for,effecting'the'stopping of the motor to bring the car to the floor level. g

11. In a ,control system for a motor-operated elevator car movable in a hatchway relative to one or more oors, in combination; a light-controlled unit carried by the car including a, light source and a light-sensitive device disposed in operative relation thereto, a space-discharge device disposed to be rendered conducting when said light-sensitive device islnot illuminated, and a filter connected in circuit with said space-discharge device forl preventing the application thereto ofu currents having frequencies diileringv disposed to be connected for energizing said space-discharge device, a shield individual to said floor and mounted in the hatchway for inter-1 cepting the rays of light falling on saidlightsensitive device from said light source, and a'slowdown relay disposed' to be energized when said space-discharge device is renderedcon ucting for effecting the stopping of the motor to bring the car to the door level.

l2. In a control system for a motor-,operated elevator car movable in a hatchway relative to one or more floors, in combination; a light-controlled unit carried by the car including a light source and a light-sensitive device disposed in operative relation thereto, a space-discharge device disposed to be rendered conducting when said light-sensitive device is not illuminated, and a filter connected in circuit with said space-discharge device for preventing the application thereto oi currents having frequencies differingl falling on said light-sensitive devicefrom said j light source, and a slow-down relay disposed to be energized when said space-discharge device is rendered conducting for effecting the stopping of theV motor to bring the car to the floor level.

i3. In a control system for a motor-operated elevator car movable in a hatchway relative to one or more doors, in combination; a light-controlled unit carried by the car including a light source and a light-"sensitive device disposed in operative relation thereto, a space-discharge device disposed to be rendered' conducting when said light-sensitive device is 'not illuminated, and a illter connected in circuit with said space-discharge device for preventing the application `thereto of currents having frequencies differing from aT predetermined frequency; a transformer having a primary winding connected to a source oi.' alternating current and a secondary winding,

' control means operable in response to a oor call and disposed to immediately effect the energize,- tion of said light source and to connect said secondary winding to energize said space-discharge device a predetermined time thereafter, a shield individual to said door and mounted in the hatchway for intercepting the rays of light falling on said light-sensitive device from said light source, and a slow-down relay disposed to be energized when said space-discharge device is rendered conducting for eiecting the stopping of the motor to bring the car to the floor level.

EDWIN H. VEDDER. 

